Device for pointing bristles



Dec. 14, 1954 F. INGRAITO 2,697,009

DEVICE FOR POINTING BRISTLES Filed April 15, 1949 INVENTOA.

ATTORNEYS.

United States Patent DEVICE FOR POINTING BRISTLES Francesco Ingraito,Verbania-Pallanza, Italy, assignor to Socita Rhodiatoce S. p. A., acorporation of Italy Application April 15, 1949, Serial No. 87,838

Claims priority, application Italy April 29, 1948 2 Claims. (Cl. 300-2)In brush-making, for a large number of applications, in particular forthe making of shaving brushes, paint brushes and the like, naturalbristles are preferred rather than monofilaments of natural, artificialor synthetic origin, because those bristles are sharp-pointed and splitand impart to the articles mentioned, the desired properties, such assoftness of contact of the ends of the brushes and better retention ofthe liquid they serve to convey.

Attempts have been made directly to obtain pointed artificial orsynthetic monofilaments, but the processes for attaining this result arevery hard to carry out.

it has also been proposed to grind the ends of various bristles ofdifferent characters. But this operation, which is ordinarily carriedout on manufactured articles (paint brushes, shaving brushes, brushes ingeneral) has the disadvantage of abnormally shortening, by excessiveWear, the peripheral bristles of these articles and of insufficientlyaffecting those of the central portion.

it has equally been proposed to sharpen natural monofilaments by combingthem by means of emery-coated points, but the latter are of extremelydiflicult manufacture.

Finally, it has been proposed to split or flower natural monofilamentsby attacking them with pointed needles or sharp teeth, which penetrateinto the matter and split it up lengthwise: however, those devices getblunt very quickly and it takes an abnormally long tlme to obtainmonofilaments with satisfactory flowering, which moreover is ratherirregular; whence it is advisable frequently to sharpen the needles andteeth, and even to replace these members, and such operations arecostly.

Moreover, even with the last-mentioned process, it is impossible inpractice to obtain monofilaments having the appearance and properties ofnatural bristles.

Now it has been found, as a result of the invention, that it is possibleto impart to any monofilament or bristle of whatsoever origin, natural,artificial or synthetic, the desired refining and flowering,particularly with the appliances hereinbefore referred to,

The present invention relates to a method of treating natural,artificial or synthetic bristles, and provides the method and apparatusfor subjecting the free ends of said bristles to the action of theneedles-of a card wire band moving at high speed, in such a manner thatthe bristle ends be struck by the points of the needles, and ofprotracting this action until the bristles get sharpened and flowered attheir ends. The invention further provides new natural, artificial orsynthetic bristles characterized in that the ends of the individualbristles are sharp-pointed and flowered at the same time.

There are numerous models of cards adapted for the carrying out of theprocess according to the invention; those of the scratch-card type arethe most suitable. The needles used with this typehave the pecularity ofbeing made of sufliciently hard metal and of offering, nevertheless, acertain elasticity owing to their shape and to the manner in which theyare fastened to their base at one of their ends; they are of practicallyconstant cross-section and they are arranged parallel to one another.Cards are to be chosen of suitable type as'to their shape, thickness,free length of the needles, density, that is to say number per unitarea, kind of base orsupport, etc. and those skilled in the art will bereadily able to determine optimum conditions in each individual case aswell as the most favourable speed and duration of operation.

The translatory movement of the card striking the ends 2,697,009Patented Dec. 14, 1954 "ice their ends subjected to sharpening and ifneeded to flowering; this free length of bristle should in general begreater than the length of the card needles, and it may reach the totallength of utilization of the sharpened and flowered bristles, as is thecase, for example, if treatment of the bristles is effected while thesaid bristles are already mounted on the appliance. Following this freelength, following the pressure exerted on the bristles during treatmentpressure means here the eifort developed to cause the monofilaments topenetrate between the needles of the moving card), following thedirection in which the bristles are exposed with respect to the movementof the card, there are obtained different lengths of refining. Floweringappears to get more and more general as the treatment according to theinvention is protracted. At any rate, by controlling the differentfactors, notably the duration of operation, it is possible to obtainbristles either only sharp-pointed in general, or, on the contrary, bothsharpened and flowered entirely, or even an assembly with bristlesmostly sharpened and partly flowered.

It should be understood that the optimum operating conditions areessentially a function also of the material constituting themonofilaments as well as of their thickness; these conditions, however,can be easily determined by those skilled in the art.

It is easy to provide a supporting member for the bristles beingcontrolled in such a way as to enable one to adjust the penetration ofthe bristles between the needles as well as to make the treatmentaccording to the invention uniform for the whole of the bristles, byrotating about an axis parallel to their general direction, rotationbeing imparted to the whole of the bristles tied in bunches or mountedon the appliance.

If desired, the monofilaments may undergo external I cooling during theoperation, for example by water or air-cooling but such arrangementproved to be superfluous in the majority of cases.

The treatment may be effected on straight bristles, whether they becylindrical or frusto-conical, notably such as are obtained with certainmanufactures; however, it is also possible to utilize non-rectilinearmonofilaments, for example those having undergone previous treatment andpermanent deformation, in particular those of undulated shape, which iseminently favorable to expansion if mounted on the appliance, and,moreover, entails better retention of the substances the bristles of thebrush are designed to convey.

It is equally possible to utilize monofilaments having undergoneprevious auxiliary treatments, for example treatment of swelling,dyeing, pigmenting, fireproofing, or rendering water-shedding orinsoluble.

Among the kinds of filaments or bristles to which the invention may bespecially applied, there may be mentioned:

The hair of certain quadrapeds, for example horse-hair;

The filaments or bristles obtained from regenerated cellulose, possiblytreated with phenoplasts or aminoplasts;

The filaments or bristles obtained from cellulose ethers or esters andmore particularly from cellulose tri-estcrs;

The filaments or bristles obtained from polyvinyl derivatives, such aspolyvinyl chloride pure or superchlorinated, vinyl chloride co-polymerswith other vinyl derivatives (vinyl acetate, vinyl cyanide, vinylidenechloride), polyvinyl cyanide, polyvinylidene chloride;

The filaments or bristles from synthetic linear superpolycondensatessuch as superpolyesters, superpolyurethanes, and particularlysuperpolyamides, which superpolycondensates may be simple or mixed ortreated with foreign substances such as aminoplasts; as tosuperpolyamides, particularly interesting results have been attainedwith superpolyhexamethyleneadipamide, superpolyhexa- 3methylenesebacamide, superpolyamide from 6-aminoexanoic acid orll-aminoendecanoic acid.

The accompanying drawing shows by way of example a preferred embodimentof a device for carrying out the invention.

In said drawing, 2 indicates a bristle holder carrying bunches ofbristles 3 to be treated. This holder 2 is rotatable upon a supportingshaft 1 and longitudinallyadjustable along said shaft to vary the depthto which the bristles 3 are penetrated by the needles 4 of card wirebands mounted on and driven by the rolls 5 in the direction indicated bythe arrows and in a plane substantially normal to the plane of rotationof the bristle holder 2. The drive assembly is conventional, and will besufliciently understood from the more or less diagrammaticrepresentation. Of course, the bristles might be held against a movingcard by other means or by'hand, but the arrangement shown isparticularly advantageous in that it enables absolutely regular oruniform treatment.

The monofilaments according to the invention find particularlyinteresting applications, as already stated, in brush-making, notably inthe manufacture of paintbrushes, shaving brushes, varnish brushes andcertain other domestic, sanitary or industrial brushes.

The invention has been hereinbefore described with particular referenceto a moving scratch-card whose needles come to strike the ends offixedly supported bristles. It is self-evident that recourse may be hadto any appropriate device comprising metal needles having features likethose of the said scratch-cards, that is to say, notably having constantcross-section, shape of circumflex accent, arrangement parallel to eachother and one of their ends secured to a suitable supporting member.Moreover, the card may be fixed and the bristles displaced, or even thecard and bristles may be simultaneously displaced in contrary senses.

It is surprising that by carrying out the process according to theinvention, monofilaments are obtained which from the first are perfectlyfinished and free from any deterioration, although it might be expectedthat intensive processing would be necessary to cause the desiredmodifications and would entail such increase of temperature as to makethe monofilaments melt or soften, viz. be depolymerized.

It is also quite unexpected that the utilization of needles having aconstant cross-section, that is to say, having no sharp points at all,are able in particular to cause quick and regular splitting ofmonofilaments'constituted by such substances. It has even been foundthat it is possible to split the end of one individual bristle into alarge number of parts (up to fifteen such parts could in one case becounted) and there was nothing to lead one to expect, a priori, such aresult, which result, incidentally, is of considerable practicalinterest.

At last, and contrary to expectation too, it has been found that theneedles have particular durability, resetting becoming necessary onlyafter a long time of use.

The invention is illustrated, merely by way of indication, by thefollowing examples:

Example 1 On the shaft of a 0.7 H. P. electric motor, adapted to turn at2800 R. P. M., a wooden disk of 190 mm. diameter and 30 mm. thickness isfitted, which corresponds to a linear peripheral speed of about 1650metres per minute. On the periphery of said disk a scratch-card ismounted, which is provided with steel needles shaped in the form of aWide open V (about 130 angle), the two branches of which are each about3 mm. long; the diameter of the needles is 0 of mm. and their density is100 a cm. these needles have been clasped onto a soft foundation ofabout 2 mm. thickness and constituted by the assembly of four layers ofa cotton fabric glued to each other and coated with a rubber film. Inthis way, the needles get a certain flexibility due to both thecharacter of their foundation and their shape.

With bristles of polyhexamethyleneadipamide of 7 of mm. diameter afterdrawing, which were previously undulated in a manner known in itself, abunch of 30 mm. diameter is formed. This bunch is mounted in asupporting member adapted to allow for turning the bunch within it aboutits axis; the bunch is previously adjusted in said support in such a waythat the bristles are-arranged radially with respect to the disk, thefree lengths of the bristles being '50 mm. and the distance between thefree ends of the needles and the fastening points of the bunch nearestto the disk being 30 mm.

The motor is made to'run, while the needles are in contact with the endsof the bristles, and after 2 minutes, operation is stopped. At thistime, it can be seen that the bristles have got their ends regularlysharpened over a length of about ten mm. and that almostall of thempresent at their ends each two, three, four or'even more sprigs of from0.5 to 1 mm. length. A bunch of this kind is particularly suitable forthe manufacturing of shaving brushes. V

Example 2 The operations of Example 1 are carried out with the followingvariations:

Bristles of polyhexamethylenesebacamide are used;

The said bristles, non-undulated, are 70 mm. long and are offrustoconical shape; large diameter 0 of mm.. small diameter of mm.;

A scratch-card is used provided with needles having square cross-sectionof of mm. side-length, presenting 200 needles a cmfl;

The motor (1 H. P.) turns at 3,200 R. P. M.;

The bristles are mounted, of courseat their larger ends, in the ferruleof a round paint-brush, which is rotated about its-axis duringoperation.

In this way, apaint-brush is obtained with sharp-pointed and floweredends and, therefore, having excellent retention power for paint.

Example 3 Operation is carried out-as in Example 1, except:

Bristles of pure polyvinyl chloride are used, having of mm. diameterafter drawing;

The motor turns at 2,500 R. P. M., and operation is made to last fourminutes.

An ultimate bunch is obtained which from all points of view is analogousto a product as obtainable from natural bristles.

What is claimed is:

1. A device for pointing and flowering the free ends of monofilaments,comprising in combination a rotary cylindrical needle support, a groupof metallic needles of substantially constant cross section and-smoothsurfaces projecting radially from the periphery of said support, adiscshaped member carrying at its outer perimetral annular portion thebristles to be pointed and flowered, means for adjusting the axialposition of said disc-shaped member to bring the bristles to be pointedand flowered into contact with said needles, and means for rotating saidneedle support in a plane substantially normal to the plane of rotationof said bristle-carrying member.

2. A device for pointing and flowering the free ends of monofilaments,comprising in combination a plurality of rotary cylindrical needlesupports equipped with metallic needles of substantially const'ant crosssection and smooth surfaces projecting substantially radially from theperiphery of said supports, eachof said needle supports being arrangedupon'a shaft normal to the axes of rotation of said supports, adisc-shaped member rotatable about said shaft and carrying at itsperimetral ring-portion the bristles to be pointed and flowered, meansfor adjusting the axialpositionof said member on said shaft to bring thebristles to be pointed and flowered into contact with said needles, andmeans for rotating said supports in a plane substantially normal to theplane of rotation of said bristle-carrying member.

References Citedin the file of this patent UNITED STATES PATENTS NumberName Date 425,044 McKirn Apr. 8, 1890 1,627,704 'Izawa May 10, 19272,207,156 Neville July 9, 1940 2,292,905 Smith Aug. 11, 1942 2,353,683Martines July 18, 1944 FOREIGN PATENTS Number Country Date

